JOHANNESBURG – The rhino’s rescuers gave her a name: Hope. Poachers in South Africa had darted the rhino with a tranquilizer and hacked off her horns while she was sedated, leaving the animal with a horrific wound covering much of her face. A couple of days later, staff on a wildlife reserve found the grievously injured rhino – alive. Last week, veterinarians operated on the 4-year-old female, a rare survivor of increasing attacks by poachers who killed more than 1,200 rhinos last year in South Africa, home to most of the world’s rhinos.